In the past, 40-inch (″) class TVs were mainstream products, but many consumers now buy 50″ class TVs and even 60″ class TVs. When the size competition was over, resolution competition began. Even a year ago, full high definition (HD) (FHD) class TVs belonged to an advanced model, but ultra HD (UHD) TVs now have been rapidly spread on the market.
Recently, the display market has evolved from large-area, high-resolution competition to color competition. For this reason, competition for the production of a display with excellent color has recently emerged.
A liquid crystal display (LCD) displays an image using optical properties of liquid crystals, wherein, since a liquid crystal panel displaying the image is a non-emissive device which is not self-luminous, the liquid crystal display has a structure including the liquid crystal panel as well as a back-light unit which is disposed on a rear surface of the liquid crystal panel to provide light to the liquid crystal panel.
A liquid crystal display has advantages of a small thickness, a light weight, a small consuming power and a low driving voltage when compared to other displays. On the contrary, the liquid crystal display is one step behind the other displays in the sense of color. The color reproduction range of a CRT which is now disappearing amounts to NTSC 80%, and a PDP that has been released recently can achieve the level of NTSC 90%. In addition, an OLED which receives much attention as a next-generation display, may attain up to NTSC 100%. However, an LCD TV may attain at most NTSC 72%.
Accordingly, there is a need to solve the limitations of the LCD to survive in the depressed display market.
In particular, it is required in the field to develop a technology for improving the color gamut of the conventional LCD, and a new technology for compensating brightness decrease, which may be accompanied by the improvement of the color gamut.